Recording apparatus



G. G A. ERICS SQN RECORDING APPARATUS Filed Sept. 15, 1942 2Sheets-Sheet 2 g. I II II R III III H11 1 H I IHHH III] I 1H1 I f l IIII! III! INVENTOR GUSTAF GOTE ALBIN ERICSSON ATTORNEY Patented Oct. 22,1946 RECORDING APPARATUS Gustaf Giite Albin Ericsson, Lund, Sweden, as-

signor to A.-B. Ljussignaler, Lund, Sweden, a corporation of SwedenApplication September 15, 1942, Serial No. 458,412 In Sweden June 10,1939 2 Claims.

The present invention refers to improvements in recording apparatus forcontrolling workingmachines and has for its object to increase thecapacity of such apparatus.

A primary object of the present invention is the embodiment of recordingapparatus whereby it is possible, with a relatively compact device, toobtain a complete graphical record of the individual operation of aplurality of working-machines.

This is realized, briefly stated, by a novel'relationship of parts,hereinafter described in detail, and including traveling record strips,electromagnetically operated styli and an electromechanical arrangementfor correlating the working-machines, the styli and the record strips,as hereinafter more fully set forth.

Further objects and advantages of the invention will be evident to theexpert in the art from the following disclosure.

The invention will be more particularly described in a preferredembodiment with reference to the accompanying drawings, in which:

Fig. 1 is a fragmentary plan view partly in section of a recordingapparatus in which the invention is incorporated, the section beingalong line II of Fig. 2, and parts being omitted for the sake ofclearness,

Fig. 2 is a fragmentary view, partly in section along line 22 of Fig. 1,illustrating the mounting of a stylus and its relationship to adjacentparts of the apparatus,

Fig. 3 shows a record made by means of the apparatus, and

Fig. 4 is a circuit diagram of the device according to the invention.

Referring to the drawings, the apparatus partly shown in Figs. 1 and 2comprises a number of rows or groups of horizontal electromagnets Iwhich, at their rear ends, are mounted in a supporting plate 2. On everyalternate electromagnet, in the space between this and one of theadjacent magnets, there is provided an armature 3 which is carried by anarm 4 which is pivotally mounted at the front end of the electromagnet,so that it can swing back and forth in a horizontal plane, and extendsinto engagement with a vertical leaf spring 5 which is fixed with itsupper end in the frame 6 of the apparatus. The arm 4 is made of sheetmaterial and is mounted as shown on the drawings. The front end of thearm 4 is twisted a quarter of a revolution and provided with a notch bywhich it freely embraces the edge of the leaf spring 5 near its freeend, as will clearly be seen from Figs. 1 and 2. At its free end theleaf spring 5, as is shown in Fig. 2, carries a stylus 'I which makes arecord on a strip of paper fed at a constant speed over a roller 8. Eacharmature 3 in its position of rest has its inner free end situated atequal distances from both electromagnets between which it is situated,so that it is attracted by either of these magnets that is energized bycurrent impulses and makes an equal deflection at one side or the other,the leaf spring 5 and the stylus carried therebymaking correspondingdeflections at one side or the other of a median position. At eachdeflection the stylus 1 makes a horizontal dash on the paper strip, sothat the record will get the appearance shown in Fig. 3.

For preventing the stylus I from being actuated by both electromagnets Isimultaneously there is provided a special impulse generator which isconstructed so as to deliver the impulses to the electromagnets atdifferent times. This impulse generatorfat the same time serves toproduce a plurality of different impulse series for actuating the sameelectromagnet, so that the latter and the associated stylus may be usedfor controlling a number of working-machines. This is illustrateddiagrammatically in Fig. 4. On each working-machine to be controlled bymeans of the recording instrument a contact 9 is provided so as to beclosed, by the closing of the corresponding switch 9a, at the startingof the corresponding machine and remain closed as long as the machine isoperating. Each contact 9 is connected in a circuit together with anormally opened impulse contact I0, preferably at least two or, ifdesired, more such circuits being connected in parallel with one end ofthe winding of one of the electromagnets I, while the other end of saidwinding is connected to a source of current. The impulse contacts I0 areactuated by cam means comprising a number of cams II which are mountedon a common shaft I2 which is driven at a constant speed, for example bya synchronous motor. When an impulse contact In is momentarily closed bythe operation of a passing raised portion of the associated cam II andif the machine contact 9 connected in the same circuit as this impulsecontact is closed, the corresponding electromagnet I will attract itsarmature, the stylus making a horizontal dash on the paper strip. Thecams II which actuate impulse contacts In connected in circuitsassociated with the same electromagnet are provided with a differentnumber of raised portions mounted in different angular positions, sothat the circuits through the electromagnets can never be closed at thesame time and so that they are closed an equal number of times per unitof time, whereby a density of recording dashes on the paper strip whichis characteristic of each circuit or working-machine is obtained. Theserecordings indicate what machine or machines have been in operation at acertain time. If a plurality of machines are in operation simultaneouslythe recording dashes for the various machines will be intercalatedwithout coinciding, so that a diagram of the appearance which is seen inFig. 3, e. g. to the left of the median line, is obtained. The simplestrokes correspond to the cams H which have but a single raised portionor cam element. The triad strokes correspond to those with three raisedportions or cam elements. Furthermore, the raised portions of all thecams II which govern the circuits of two electromagnets I having acommon armature are angularly offset in such a way that theseelectromagnets can never actuate the armature simultaneously. On theother hand, cams which are not associated with the same electromagnetcan very well have the same number of raised portions, since there isnothing to prevent the recording from taking place with the same densityof dashes at both sides of the median line.

It will be evident that with the apparatus shown in Fig. 4 one maycontrol four workingmachines by means of a single stylus controlled bytwo electromagnets I. Theoretically, the number can be further increasedby providing a plurality of circuits for each electromagnet togetherwith associated cams having raised portions arranged in difierent ways.In the case of a number greater than four it will be found difficulthowever to distinguish the recordings by means of the density of thedashes.

The impulse contacts In and the cams II not only cooperate with a singlepair of electromagnets but are common to all electromagnets in theapparatus, each impulse contact being connected in a circuit througheach pair of electromagnets as indicated in Fig. 4, so that each of thevarious impulse series is common to several machines but are recorded ata particular place on the paper strip for each machine. Where fourmachines are controlled with each stylus thus only four impulse contactsand four cams are needed.

What I claim and desire to secure by Letters Patent is:

1. A recording system of the character described, comprising a stylusfor recording on a travelling strip, an electromagnet for operating saidstylus, a pair of machine controlled switches connected in parallel inthe circuit of said electromagnet, and a corresponding number of camcontrolled impulse contacts connected in series each with one of saidmachine controlled switches in the circuit of said electromagnet, eachcam control comprising a different number of lobes, the lobes of thediiierent cams for the different impulse contacts being out of phasewith one another.

2. A recording system of the character described, comprising a stylusfor recording on a travelling strip, two electromagnets for operatingsaid stylus by resiliently moving it to one side or the other from anormal median position upon energization of one or the other of the twoelectromagnets, each of the two electromagnets having an energizingcircuit comprising a pair of machine controlled switches connected inparallel in the circuit, and cam controlled impulse contacts connectedin series each with one of the machine controlled switches in thecircuits of the two electromagnets, each cam control comprising adifferent number of lobes, the lobes of the different cams for thedifferent impulse contacts being out of phase with one another.

GUSTAF GOTE ALBIN ERICSSON.

